In the related art, a technique is disclosed in which, a flow route of the fuel is not bent while the fuel flowing into a fuel injection hole reaches an outlet from an inlet of the fuel injection hole, and atomization of the injected fuel is promoted by obtaining the expansion and contraction of the volume without particularly increasing the discharging pressure of a fuel pump. In recent years, the regulations of exhaust gas of automobiles have been strengthened, and internal combustion engines of automobiles have been required to reduce particulate matter such as harmful exhaust gas HC (hydrocarbon) or soot. This exhaust matter is generated in such a manner that the fuel adhering to a wall surface in a cylinder or an intake valve due to impact causes an unburnt state so that the flame has difficulty propagating, or the fuel becomes locally rich. In order to suppress such circumstances, it is necessary to shorten the spray itself so that the spray does not collide with the wall surface in the cylinder, and to improve a degree of freedom for laying out the spray so that the spray does not collide with the intake valve and the like. In the related art, in the injection hole, the sectional area of a flow path of the fuel is changed in a flowing direction, swirling velocity components are generated in the section perpendicular to a central axis of the injection hole (regardless of velocity components in an injection direction), and the spray is diffused by the swirling velocity components when the fuel is injected from the injection hole. As a result, the spray can be shortened.